Interpretive Summary: To evaluate the filling and emptying of the digestive system, hens were fed and then placed into transport coops prior to processing over a two-day period. Hens were fed at 6 am on Day 1 and after access to feed for 0, 2, 4 and 6 hours were placed into coops and half of the hens from each time period were either immediately processed or were held in the coops overnight and processed the following morning, Day 2. During processing the digestive system was removed from the carcass and was separated and weighed in three adjacent segments; the crop (feed storage), the stomach (chemical and mechanical digestion), and the intestines (absorption). Hens processed on Day 1, after access to feed for 2 hours had attained peak intestine weight, and after access to feed for 6 hours peak crop and stomach weights were attained. Hens processed on Day 2, did not differ in crop or intestines weight, but stomach weight was significantly lower for the hens not fed on Day 1 prior to cooping compared to those hens fed on Day 1 and cooped after 2, 4, or 6 hours. However, hens processed on Day 2, had stomach weights that were identical to those hens processed on Day 1 and cooped at 0 hour. Clearance of ingesta and feces from the crop, stomach, and intestines readily occurred while hens were held overnight in transport coops without access to water. These findings suggest that when the digestive tracts of processed hens contain significant crop or stomach content, they were likely processed on the day they were placed into transport coops. Furthermore, holding fed hens in transport coops overnight did not slow the passage of ingesta through the digestive tract and did result in the clearance of contents from all three segments of the digestive tract. Minimizing the amount of content remaining in the tract during processing, will reduce the potential for contamination of the carcass with bacteria in the event that contents leak for the tract during processing.

Technical Abstract:
To evaluate the filling and emptying of the alimentary track, broiler breeder hens were cooped and processed over a two-day period. Hens were fed at 0600 on Day 1 and after access to feed for 0, 2, 4 and 6 h were placed into coops. Half of the hens from each pen were either immediately processed or were held in coops overnight and processed the following morning, Day 2. The alimentary tract was excised from the carcass and was separated and weighed in three segments; the crop, proventriculus and gizzard, and the intestines. Hens processed on Day 1, after access to feed for 2 h had attained peak intestine weight (176 g), and after access to feed for 6 h peak crop weight (95 g) and peak weight for the proventriculus and gizzard (78g) were attained. Hens processed on Day 2, did not differ in crop (12 to 14 g) or intestines weight (140 to 162 g), but proventriculus and gizzard weight were significantly lower for the hens not fed on Day 1 prior to cooping (54 g) compared to those hens fed on Day 1 and cooped after 2, 4, or 6 h (62 to 63 g). However, hens processed on Day 2, had proventriculus and gizzard weights that were identical to those hens processed on Day 1 and cooped at 0 h (63 g). Clearance of ingesta from the crop, proventriculus and gizzard, and intestines readily occurred while hens were held overnight in coops without access to water.